Training craft for ultrarunners. What actually works out there, and why. UTMB 2026 Cutoff Times: The Math Behind 46 Hours UTMB 2026 starts August 28 in Chamonix. Full cutoff math at all 13 checkpoints, why Courmayeur claims the most DNFs, and what reaching Champex-Lac means. Ike Lacey · Aug 19, 2026 Running Science Garmin Running Economy Explained for Trail Runners Garmin's running economy metric arrived. Here's what ml/kg/km actually measures, why your trail runs don't count, and what your Strava history fills in. Ike Lacey · Aug 14, 2026 Javelina Jundred Race Strategy: Lap Splits for Every Finish Goal The Javelina Jundred's 5-loop structure hides lap 1 damage until lap 3. Lap pacing math for 22, 24, 26, and 28-hour finish goals, with the heat window built in. Ike Lacey · Aug 12, 2026 The 20 Days Between Leadville and Wasatch You finished Leadville on Aug 22. Wasatch starts Sept 11. Here is what Grand Slam runners do in the 20-day window between two altitude hundreds. Ike Lacey · Aug 7, 2026 Eccentric Training for Downhill Running: A 6-Week Protocol Descents destroy unprepared quads. Here's the repeated bout effect science and a 6-week eccentric training protocol for Wasatch and Run Rabbit Run. Ike Lacey · Aug 6, 2026 Ultra Taper: Why Three Weeks Is a Different Clock The ultramarathon taper runs 3+ weeks because structural muscle damage clears on a slower clock than fitness fades. What's happening in the body, and how to hold the quiet. Ike Lacey · Aug 5, 2026 NYC Marathon Course Guide: Five Bridges, 875 Feet NYC Marathon 2026 has five bridges that compound into a miles-23-25 collapse. Here's the elevation data for each crossing and how to train for the course. Ike Lacey · Jul 31, 2026 Should I Nap During a 100-Miler? The Data Decides 83% of 100-mile finishers skip the nap. Whether you should is a function of one number: your projected finish time. Here's the framework. Ike Lacey · Jul 30, 2026 Wasatch Front 100 Prep: Heat, Cold, and the Re-Entry Rule Wasatch Front 100 starts September 11: 24,000 feet, extreme temperature swings, and a re-entry penalty no other major 100 carries. Cutoff math and prep inside. Ike Lacey · Jul 29, 2026 Running Science Why You Still Feel Flat Weeks After a 100-Miler New science names the post-ultra flatness that outlasts sore legs: red blood cell damage that scales with distance. What the study found, and what it means for recovery. Ike Lacey · Jul 23, 2026 Leadville 100 Cutoff Times: The Math Behind 30 Hours The Leadville 100 starts at 4 AM on August 22. Here's the cutoff math: Winfield, Twin Lakes inbound, Mayqueen, and what your training data says about 30 hours. Ike Lacey · Jul 22, 2026 Why Women Keep Winning Ultras Outright Fat oxidation, pacing splits, and muscle fiber data explain why ultra distance closes the sex performance gap, and what Entrekin's Cocodona win proves. Ike Lacey · Jul 17, 2026 Running Science Your Zone 2 Ceiling Is Wrong — Here's How to Fix It Your watch computed your zone 2 using a formula with no lab validation. New 2025 research shows the error can reach 15–20 bpm. Here's the 20-minute field test that fixes it. NavRun Team · Jul 16, 2026 Is Your Chicago Training on Track? The 3-Signal Check 4–6 weeks into fall marathon training? Here's the 3-signal data check, heat-adjusted pace drift, HR creep, and mileage ramp, that tells you if your Chicago goal time still holds. Ike Lacey · Jul 15, 2026 Running Science Low HRV During a Training Block: A Diagnostic Guide for Ultra Runners Before you back off a session, diagnose why HRV is low: training load, degraded sleep, or the feedback loop driving both. A framework for ultra runners. Ike Lacey · Jul 10, 2026 Connect Any AI to Your Running Data Connect Claude, ChatGPT, or any AI to your NavRun data and ask real questions about your training. Free, read-only, and it never sees your Strava password. Ike Lacey · Jul 9, 2026 Running Science HRV Explained: The Daily Training Signal ACWR Misses HRV answers the daily question ACWR can't: should today's hard session happen? A practical decision framework for runners with Garmin, Whoop, or Oura. Ike Lacey · Jul 9, 2026 UTMB 2026 Training: Vert Targets for the Final 7 Weeks UTMB 2026 starts August 28. Here are your weekly vert targets for the final 7 weeks, the heat block decision if you're not alpine-based, and the exact taper week. Ike Lacey · Jul 8, 2026 Fall Marathon Training in Summer Heat: The Two-Phase Plan Your fall marathon block is already running in summer heat. Here's the two-phase structure that keeps your training honest through week 16. Ike Lacey · Jul 3, 2026 Your Summer Pace Is a Lie: The Dew-Point Adjustment Your summer running pace looks terrible, but the algorithm doesn't know it's 78°F with a 68°F dew point. Here's the math that makes your fall marathon training data honest. Ike Lacey · Jul 2, 2026 Training Physiology Heat Acclimation for Runners: Two Paths, One Block Summer's spiking HR isn't a problem to survive, it's a 10-day stimulus. The science, two protocols (including the 6-day HWI shortcut), and what to watch in your Strava data. Ike Lacey · Jul 1, 2026 Building Your Ultra Base: The 12-Week Foundation Phase That Makes Everything Else Work Accumulated fitness is not the same as a built ultra base. Here's the 5-signal readiness check and a 12-week base-building plan for experienced ultra runners stepping up to longer goals. Ike Lacey · Jun 25, 2026 40 Miles a Week Is Enough for a 50K (Not a 100) Training for a 50K or 50-miler on 40 miles a week is achievable -- if you spend those miles in the right order. Here's the allocation framework that actually works. Ike Lacey · Jun 19, 2026 Time on Feet: Why Mileage Fails Ultra Runners Mileage misleads ultra runners the moment terrain enters the picture. Time-on-feet targets for 50-mile and 100K training -- and how to restructure your week in hours. Ike Lacey · Jun 18, 2026 100-Mile Training Plan: A 24-Week Phase Breakdown A structured 24-week training plan for first-time 100-miler runners with ultra experience. Six phases, what each builds, the three decisions that separate finishers from DNFs, and an honest look at the life cost by phase. Ike Lacey · Jun 17, 2026 50K to 50 Miles: What Changes After Mile 35 You've finished 50Ks. But 50 miles starts a different race after mile 35, one your 50K training never touched. Here's how to close the gap. Ike Lacey · Jun 12, 2026 Training Paces Explained: The Five Zones and Why Most Miles Should Be Easy What VDOT is, the five Daniels training zones (Easy, Marathon, Threshold, Interval, Repetition), and how to get all of them from a single recent race. Ike Lacey · Jun 8, 2026 Ultra Fueling: How Many Carbs Per Hour Do You Actually Need? How many carbs, how much fluid, and how much sodium per hour for an ultramarathon, the real ranges, why gut training matters, and how to dial in your own numbers. Ike Lacey · Jun 8, 2026 Race Time Predictor: What One Race Actually Tells You (5K to 100 Miles) Enter one recent race result and get predicted finish times from 5K to 100 miles. Free, no signup. Here's the math behind it, where it works, and where it lies to you. Ike Lacey · Jun 8, 2026 How to Use a Pace Calculator (Without Blowing Up Your Race) Pace is just time divided by distance. Here's how to use a pace calculator to set even splits, why even pacing beats going out hot, and how to turn the number into a race-day plan. Ike Lacey · Jun 8, 2026 How to Connect Strava to Claude AI Strava now connects to Claude. Here's what the MCP connector does, how to set it up, and what to ask it once your runs are in the conversation. Ike Lacey · Jun 5, 2026 Ultra Marathon Speed Training (The Missing 15-25 Minutes) Speed training can improve your ultramarathon finish time by 15-25 minutes without sacrificing durability. Learn which intervals and tempos actually transfer to 50K racing. Ike Lacey · Jun 4, 2026 Running Tired: Why Consecutive Long Runs Build Ultra Fitness Learn why running tired on Sunday teaches your body the core demand of a 100-miler. Discover when to add consecutive long runs and how to validate the adaptation in your training data. Ike Lacey · May 29, 2026 Your First 50K Training Plan: 12 Weeks to Ready Build a 50K training plan designed for ultrarunning durability, not speed. Learn the metrics that predict readiness and a proven 12-week training structure.

Ike Lacey · May 27, 2026 Ultra Elevation Data: How to Read Vert Your watch records elevation gain on every run. Here's how to actually use those numbers to plan ultra training and predict race performance. Ike Lacey · May 21, 2026 Training Splits That Predict Ultra Race Day Your training splits already know how your ultra will go. Five signals to read in your data, weeks before the start line. Ike Lacey · May 20, 2026 Western States 100 Prep: Canyons, Heat, Field How to train for Western States 100, canyon climbs, downhill quads, heat acclimation, and pacing the most competitive ultra in North America. Ike Lacey · May 19, 2026 100-Miler Readiness Checklist (Data) A data-based readiness checklist for your first 100-miler. Use your Strava training metrics to honestly answer: are you actually ready? Ike Lacey · May 14, 2026 Injury Prevention ACWR Explained: Your Watch's Hidden Metric Your GPS watch calculates ACWR every week but never explains it. Here's how ultra runners actually use training load data to avoid injuries. Ike Lacey · May 13, 2026 Strength Training for Ultra Runners The 9 exercises that prevent injury and build durability for 50K to 100-mile races. Plus a 12-week programming guide for ultra runners. Ike Lacey · May 12, 2026 Ultra Aid Station Strategy: In and Out Fast How to handle ultra aid stations in under 5 minutes without underfueling. The pre-arrival checklist, in-station workflow, and downstream bonk math. Ike Lacey · May 6, 2026 Strava vs TrainingPeaks vs NavRun: Ultras Honest comparison of Strava, TrainingPeaks, and NavRun for ultra runners. What works for 100-mile training, what doesn't, and what to use when. Ike Lacey · May 5, 2026 Ultra Running After 40: The Masters Edge Why runners over 40 dominate ultras, the science of masters performance, recovery, and how to train as your body changes. Ike Lacey · Apr 29, 2026 Ultra Mandatory Gear: Pack Smart, Not Heavy What ultra runners actually carry vs what stays in the drop bag. A gear-by-gear breakdown of mandatory kit, dead weight, and pack organization. Ike Lacey · Apr 28, 2026 The Mental Game of Ultra Running Named mental frameworks ultra runners use when the brain says stop. The pain cave, the 10-minute rule, chunking, mantras, and reframing pain. Ike Lacey · Apr 23, 2026 Ultra Race Post-Mortem: Read Your Data Your ultra race splits, heart rate, and pace data hold the forensic evidence of where you left time. Here's how to read them. Ike Lacey · Apr 22, 2026 Back-to-Back Long Runs: Data Framework A 6-metric framework to measure if your back-to-back long runs are producing adaptations. Track ultra training effectiveness using Strava data. Ike Lacey · Apr 21, 2026 5 Weekly Training Numbers for Ultras The 5 numbers ultra runners should check every Monday. Learn which weekly training metrics actually predict race readiness and injury risk. Ike Lacey · Apr 16, 2026 Running Science Ultra Recovery Timeline: 50K to 100Mi Science-based recovery timelines after ultramarathons. How long to rest after a 50K, 50-miler, 100K, or 100-miler, and when to start running again. Ike Lacey · Apr 14, 2026 Injury Prevention Ultra Overtraining: 7 Warning Signs Spot overtraining before it sidelines you. Learn the 7 warning signs ultra runners miss and how to monitor training load without guessing. Ike Lacey · Apr 9, 2026 Injury Prevention 6 Injury Prevention Habits for Ultras The 6 daily habits that keep high-mileage ultra runners healthy. Science-backed injury prevention for 50K to 100-mile training. Ike Lacey · Apr 8, 2026 Racing Ultras at Altitude: A Sea Level Guide How altitude affects ultra performance and a practical prep plan for sea level runners racing above 5,000 feet. Acclimatization, pacing, and fueling tips. Ike Lacey · Apr 7, 2026 Real Food for Ultras: What to Eat Specific real food options ultra runners use during 50-mile and 100-mile races. Includes what to carry, what to grab at aid stations, and when to eat what. Ike Lacey · Apr 2, 2026 Ultra Hydration: Sodium, Sweat, Safety How much sodium you actually need per hour during an ultra, how to test your sweat rate, and how to avoid hyponatremia. Science-backed hydration guide. Ike Lacey · Apr 1, 2026 Gut Training for Ultras: A 12-Week Plan A week-by-week gut training protocol for ultra runners. Build race-day nutrition tolerance so your stomach cooperates at mile 60. Ike Lacey · Mar 31, 2026 Ultra Fueling 101: Calories Per Hour How to calculate your calorie targets and build a nutrition plan for 50K to 100-mile ultras. Includes a per-hour fueling framework. Ike Lacey · Mar 26, 2026 When to DNF an Ultra: A Framework A clear decision framework for when to drop from an ultramarathon and how to process a DNF without regret. Physical, mental, and contextual factors. Ike Lacey · Mar 25, 2026 How to Crew and Pace an Ultra Runner The complete guide to crewing and pacing an ultramarathon. Gear checklists, aid station tactics, night pacing tips, and the mistakes that cost runners hours. Ike Lacey · Mar 24, 2026 Surviving the Night in a 100-Miler How to train for, gear up, and mentally survive the dark hours of a 100-mile ultramarathon. Practical strategies from sports science and race experience. Ike Lacey · Mar 19, 2026 Power Hiking for Ultras: A Guide Learn power hiking technique, when to hike vs run, and how to train the skill that saves your legs and wins ultramarathons. Free training tips inside. Ike Lacey · Mar 17, 2026 Trail Running for Beginners: Start Here Road runner going off-road? Learn the gear, technique, and training shifts you need for a safe, fun transition to trail running. Ike Lacey · Mar 17, 2026 How to Periodize Your Ultra Season Racing 50Ks, 50-milers, and 100s in one year? Learn how to structure your ultra season with A/B/C race tiers, recovery blocks, and smart periodization. Ike Lacey · Mar 12, 2026 How to Run a Faster 5K: PR Workouts Break your 5K PR with proven workouts, race-day execution tips, and a data-driven approach to finding your realistic goal pace. Ike Lacey · Mar 11, 2026 Race Day Pacing: Negative vs. Even Splits Negative splits, even splits, or positive splits, which pacing strategy leads to a faster race? The science, the tradeoffs, and when to trust the plan. Ike Lacey · Mar 10, 2026 Trail vs Road: Why Your PR Won't Map Your road PR means nothing on trails. Learn why pace drops 10-20%, how to set realistic trail goals, and why effort matters more than splits. Ike Lacey · Mar 10, 2026 Marathon Taper: Rest Without Losing Fitness Master the marathon taper: cut mileage correctly, keep intensity, and arrive at the start line fit, fresh, and ready to PR. Week-by-week guide. Ike Lacey · Mar 9, 2026 Your Strava Data Is Missing the Big Picture Strava tracks your runs, but it won't warn you about injury risk, predict your race time, or build your next training plan. Here's what's missing. Ike Lacey · Mar 8, 2026 Running Science How AI Training Plans Actually Work What really happens when AI builds your running plan. The data, the logic, the limits -- and what to look for in a good one. Ike Lacey · Mar 8, 2026